Dyeing keratin fibers, and for example human hair, with dye compositions containing oxidation dye precursors, generally known as “oxidation bases”, for example ortho- or para-phenylenediamines, ortho- or para-aminophenols, and heterocyclic bases is known.
Oxidation dye precursors are compounds that are initially uncolored or only weakly colored, which develop their dyeing power on the hair in the presence of oxidizing agents, leading to the formation of colored compounds. The formation of these colored compounds may result either from an oxidative condensation of the “oxidation bases” with themselves or from an oxidative condensation of the “oxidation bases” with coloration modifiers, or “couplers”, which are generally present in the dye compositions used in oxidation dyeing and are can be chosen, for example, from meta-phenylenediamines, meta-aminophenols and meta-diphenols, and certain heterocyclic compounds.
The variety of molecules used, which comprise on one hand “oxidation bases” and on the other hand “couplers”, allows a wide range of colors to be obtained.
An oxidative dye composition may generally also comprise at least one cationic polymer which improves the cosmetic properties of the composition. It, however, has been noted that dye compositions comprising these cationic polymers may be unstable, may have unsatisfactory cosmetic properties, and may not remain in the hair after shampooing.